[PATCH v3 2/2] tests/functional/aarch64: add raspi4b full-RAM regression test

[Marcelo Manzo <marcelomanzo@gmail.com>]

Guards against the bug fixed in the previous commit: boots raspi4b's
default 2 GiB configuration and checks that the guest actually sees
close to that (>1.9M kB), not the ~921 MiB the bug left it capped at.
Deliberately checks a threshold rather than the exact byte count of
either figure, since the precise number depends on how this specific
pinned kernel accounts for its own early reservations; the threshold
is comfortably between the two (943524 kB broken, 1905824 kB fixed,
confirmed by hand against this exact kernel/initrd).

Folded into the existing test_arm_raspi4_initrd test rather than a
new standalone boot, since it needs no machine state that test isn't
already setting up, and the functional-test suite is already slow
enough from how many separate guest boots it runs.

Signed-off-by: Marcelo Manzo <marcelomanzo@gmail.com>
---
 tests/functional/aarch64/test_raspi4.py | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/tests/functional/aarch64/test_raspi4.py b/tests/functional/aarch64/test_raspi4.py
index 35ba6c24f7..8506854d99 100755
--- a/tests/functional/aarch64/test_raspi4.py
+++ b/tests/functional/aarch64/test_raspi4.py
@@ -86,6 +86,23 @@ def test_arm_raspi4_initrd(self):
                                                 'BCM2835')
         exec_command_and_wait_for_pattern(self, 'cat /proc/iomem',
                                                 'cprman@7e101000')
+
+        # We used to get the RAM size wrong; guard against a regression
+        # (see git history for details).
+        mem_total_kb = None
+        cmd_output = exec_command_and_wait_for_pattern(
+            self, 'cat /proc/meminfo', 'MemAvailable')
+        for line in cmd_output.decode('ascii', errors='replace').splitlines():
+            if line.startswith('MemTotal:'):
+                mem_total_kb = int(line.split()[1])
+                break
+        self.assertIsNotNone(mem_total_kb, 'MemTotal line not found')
+        self.assertGreater(mem_total_kb, 1900000,
+                           'guest RAM (%d kB) is far below the ~1.9 GiB '
+                           'expected for a 2 GiB raspi4b -- the second '
+                           'memory node above the 1 GiB peripheral hole '
+                           'is probably not being added' % mem_total_kb)
+
         exec_command_and_wait_for_pattern(self, 'halt', 'reboot: System halted')
         # TODO: Raspberry Pi4 doesn't shut down properly with recent kernels
         # Wait for VM to shut down gracefully
-- 
2.47.1